The entire incident highlights a debate in the security industry about the ethics and correct approach to disclosing 0-day vulnerabilities in the software of others.

Microsoft believes that the responsible thing for Google to do would be to wait until the problem had been patched, so hackers can't use the disclosure to try and figure out what the vulnerability is so they can exploit it as well. But the counter-argument is that because the bug is already being actively exploited, the best thing Google could do was give Microsoft a smaller window to fix it, then publicly disclose it so potentially affected users can be made aware.

So what is the bug? It allows an attacker to escape from a security sandbox in Windows and execute code, compromising the target's computer. Google considers it a "critical" vulnerability.

Here's how Google describes the issue:

"The Windows vulnerability is a local privilege escalation in the Windows kernel that can be used as a security sandbox escape. It can be triggered via the win32k.sys system call NtSetWindowLongPtr() for the index GWLP_ID on a window handle with GWL_STYLE set to WS_CHILD. Chrome's sandbox blocks win32k.sys system calls using the Win32k lockdown mitigation on Windows 10, which prevents exploitation of this sandbox escape vulnerability."

A Microsoft spokesperson provided Business Insider with the following comment:

"We believe in coordinated vulnerability disclosure, and today’s disclosure by Google could put customers at potential risk. Windows is the only platform with a customer commitment to investigate reported security issues and proactively update impacted devices as soon as possible. We recommend customers use Windows 10 and the Microsoft Edge browser for the best protection."

Microsoft did not immediately respond to Business Insider's request for comment.